The present invention relates to improvements in fiber collectors, particularly for use in removing fiber and other impurities from airstream.
U.S. Pat. No. 4,778,491 to Yow, Sr. discloses a filter apparatus which is suitable for use in industrial applications such as cotton mills in which cotton dust and fibers are to be removed from airflows to reduce contamination of working atmospheres. Generally air is cleaned by blowing it through a filter medium, such as a screen or a fabric filter, which stops the solid material while allowing air to pass through, so that the passed-through air is free of the materials stopped by the filter and is therefore considerably cleaner. After a period of time, however, the filter accumulates so much of the solid material that is becomes clogged and air can no longer pass through the filter.
The apparatus of the prior patent addressed this problem by providing alternately shifting vanes downstream of the filter, so that one portion of the filter could be an active filter surface while the other is backwashed by reverse flow of air. The vanes are shifted from side to side periodically to change portions of the filter from a backwash to an active status. This apparatus has been a satisfactory solution of the air cleaning problem in smaller applications, however, it has not been found practical to scale this apparatus up to larger sizes. That is, the prior art apparatus has been suitable for handling volumes of air up to about 11,000 cu. ft./min. However, when the mill requires a larger air handling capability, such as on the order of 60,000 cu. ft./min., the apparatus simply cannot be economically made to handle the larger volumes.
Also, by directing airflows in the vanes of the prior art apparatus, somewhat higher filter differentials are required, on the order of 4 inches water level. At this pressure, seals are required between joints to prevent undue leakage and maintain the pressure, adding to the cost and complexity. Also, the higher air pressure is more expensive to generate in terms of energy being supplied to a fan or blower for the system.
Accordingly, there is a need in the art for an air cleaning apparatus and fiber collector in which larger air volumes can be handled, preferably at a lower pressure.